hey - what is that? luminance only...? no color...?
well,
this is a result of an experiment I conducted last night when seeing
was really very good for a short periode.
I used a monochromatic demo-CCD SXVF H36, my 9" TMB apo but this time
@ f/18 !
I slammed in the 2" 2* big barlow cos I wanted to see, if the system
is powerful enough to allow imaging bright small planetary nebulas -
which shall become one of my future tasks,...I hope.
singel frames were only 4 minutes 'short' and it worked nicely!
the backgroundsingal shows a very comfortable low noise at 0°celsius
ambient. even though the chip is a engen.grade type artefacts are
negligable and are easy to handle.
I also took rgb files, but in primary focus at f/9.
today when preprocessing the data the bad news came along:
after completing luminance and r,g,b seperatly I wanted to registar
and align these 2 master-frames.
but - no chance to do so! no software I used was able to stack these
two successfully!
I really did not expect this in the fist place.
I often use f/9 data and combine it with f/7 data, when I use my
reducer/flattener.
but obviously there is a big difference in what happens to the field
when trying to combine f/9 and f/18...
I would have had to crop the image so dramatically that I refused to
do so,...cos it would have been to embarrassing...
frankly, it is embarrassing enough when I admit this luminance image
you see in the full size is already a 50% crop, as my f/9 system
illuminantes the chip nicely, but fails to cast nice round stars onto
the chip all over the area.
what waste of pixels...!
so - I N E E D a decent flattener for my 9" TMB Apo f/9.
(and one is already on its way...)
in future when imaging with the barlow, which I will continue, I'll
have to do my r,g,b files also with the barlow lenses...will be
intersting to see if this works at a reasonalbe amount of exposure
time...?
data:
8.1.08:
9" f/18 (TV 2" 2* big barlow)
SXVF H36 (50% crop)
18x4 minutes single frams
7 darkframes
image acquisition: AA4
preprocessing (dark-calibration, kernel filtering, alignment,
stacking and Deconv. in maxim dl)
pre-sharpening in CCD sharp. DDP in Maxim DL.
postprocessing in PS CS2.
full size (crop) can be found here:
http://www.stargazer-observatory.com/2392-full-L.html
an enlarged crop is here:
http://www.stargazer-observatory.com/2392-enl-crop-L.html
thanks for looking,
Dietmar
